These elegant .925 Sterling Silver earrings feature high quality lab created blue opals and pave set clear Cubic Zirconia, CZ stones. There are 42 stones in all, 21 in each earring. ---Most Opals used in Jewelry are grown in a lab or, "Lab Created" like the Opals used in our Jewelry. Natural Opals are a soft stone and prone to cracking. Lab Created Opals are strong, more vibrant and have "Fire" and consistency to their coloration.